drivers/leds/leds-gpio.c

   1 /*
   2  * LEDs driver for GPIOs
   3  *
   4  * Copyright (C) 2007 8D Technologies inc.
   5  * Raphael Assenat <raph@8d.com>
   6  * Copyright (C) 2008 Freescale Semiconductor, Inc.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/leds.h>
  17 #include <linux/workqueue.h>
  18
  19 #include <asm/gpio.h>
  20
  21 struct gpio_led_data {
  22         struct led_classdev cdev;
  23         unsigned gpio;
  24         struct work_struct work;
  25         u8 new_level;
  26         u8 can_sleep;
  27         u8 active_low;
  28         int (*platform_gpio_blink_set)(unsigned gpio,
  29                         unsigned long *delay_on, unsigned long *delay_off);
  30 };
  31
  32 static void gpio_led_work(struct work_struct *work)
  33 {
  34         struct gpio_led_data    *led_dat =
  35                 container_of(work, struct gpio_led_data, work);
  36
  37         gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level);
  38 }
  39
  40 static void gpio_led_set(struct led_classdev *led_cdev,
  41         enum led_brightness value)
  42 {
  43         struct gpio_led_data *led_dat =
  44                 container_of(led_cdev, struct gpio_led_data, cdev);
  45         int level;
  46
  47         if (value == LED_OFF)
  48                 level = 0;
  49         else
  50                 level = 1;
  51
  52         if (led_dat->active_low)
  53                 level = !level;
  54
  55         /* Setting GPIOs with I2C/etc requires a task context, and we don't
  56          * seem to have a reliable way to know if we're already in one; so
  57          * let's just assume the worst.
  58          */
  59         if (led_dat->can_sleep) {
  60                 led_dat->new_level = level;
  61                 schedule_work(&led_dat->work);
  62         } else
  63                 gpio_set_value(led_dat->gpio, level);
  64 }
  65
  66 static int gpio_blink_set(struct led_classdev *led_cdev,
  67         unsigned long *delay_on, unsigned long *delay_off)
  68 {
  69         struct gpio_led_data *led_dat =
  70                 container_of(led_cdev, struct gpio_led_data, cdev);
  71
  72         return led_dat->platform_gpio_blink_set(led_dat->gpio, delay_on, delay_off);
  73 }
  74
  75 static int __devinit create_gpio_led(const struct gpio_led *template,
  76         struct gpio_led_data *led_dat, struct device *parent,
  77         int (*blink_set)(unsigned, unsigned long *, unsigned long *))
  78 {
  79         int ret, state;
  80
  81         led_dat->gpio = -1;
  82
  83         /* skip leds that aren't available */
  84         if (!gpio_is_valid(template->gpio)) {
  85                 printk(KERN_INFO "Skipping unavailable LED gpio %d (%s)\n",
  86                                 template->gpio, template->name);
  87                 return 0;
  88         }
  89
  90         ret = gpio_request(template->gpio, template->name);
  91         if (ret < 0)
  92                 return ret;
  93
  94         led_dat->cdev.name = template->name;
  95         led_dat->cdev.default_trigger = template->default_trigger;
  96         led_dat->gpio = template->gpio;
  97         led_dat->can_sleep = gpio_cansleep(template->gpio);
  98         led_dat->active_low = template->active_low;
  99         if (blink_set) {
 100                 led_dat->platform_gpio_blink_set = blink_set;
 101                 led_dat->cdev.blink_set = gpio_blink_set;
 102         }
 103         led_dat->cdev.brightness_set = gpio_led_set;
 104         if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 105                 state = !!gpio_get_value(led_dat->gpio) ^ led_dat->active_low;
 106         else
 107                 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
 108         led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
 109         if (!template->retain_state_suspended)
 110                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
 111
 112         ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state);
 113         if (ret < 0)
 114                 goto err;
 115
 116         INIT_WORK(&led_dat->work, gpio_led_work);
 117
 118         ret = led_classdev_register(parent, &led_dat->cdev);
 119         if (ret < 0)
 120                 goto err;
 121
 122         return 0;
 123 err:
 124         gpio_free(led_dat->gpio);
 125         return ret;
 126 }
 127
 128 static void delete_gpio_led(struct gpio_led_data *led)
 129 {
 130         if (!gpio_is_valid(led->gpio))
 131                 return;
 132         led_classdev_unregister(&led->cdev);
 133         cancel_work_sync(&led->work);
 134         gpio_free(led->gpio);
 135 }
 136
 137 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 138 static int __devinit gpio_led_probe(struct platform_device *pdev)
 139 {
 140         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
 141         struct gpio_led_data *leds_data;
 142         int i, ret = 0;
 143
 144         if (!pdata)
 145                 return -EBUSY;
 146
 147         leds_data = kzalloc(sizeof(struct gpio_led_data) * pdata->num_leds,
 148                                 GFP_KERNEL);
 149         if (!leds_data)
 150                 return -ENOMEM;
 151
 152         for (i = 0; i < pdata->num_leds; i++) {
 153                 ret = create_gpio_led(&pdata->leds[i], &leds_data[i],
 154                                       &pdev->dev, pdata->gpio_blink_set);
 155                 if (ret < 0)
 156                         goto err;
 157         }
 158
 159         platform_set_drvdata(pdev, leds_data);
 160
 161         return 0;
 162
 163 err:
 164         for (i = i - 1; i >= 0; i--)
 165                 delete_gpio_led(&leds_data[i]);
 166
 167         kfree(leds_data);
 168
 169         return ret;
 170 }
 171
 172 static int __devexit gpio_led_remove(struct platform_device *pdev)
 173 {
 174         int i;
 175         struct gpio_led_platform_data *pdata = pdev->dev.platform_data;
 176         struct gpio_led_data *leds_data;
 177
 178         leds_data = platform_get_drvdata(pdev);
 179
 180         for (i = 0; i < pdata->num_leds; i++)
 181                 delete_gpio_led(&leds_data[i]);
 182
 183         kfree(leds_data);
 184
 185         return 0;
 186 }
 187
 188 static struct platform_driver gpio_led_driver = {
 189         .probe          = gpio_led_probe,
 190         .remove         = __devexit_p(gpio_led_remove),
 191         .driver         = {
 192                 .name   = "leds-gpio",
 193                 .owner  = THIS_MODULE,
 194         },
 195 };
 196
 197 MODULE_ALIAS("platform:leds-gpio");
 198 #endif /* CONFIG_LEDS_GPIO_PLATFORM */
 199
 200 /* Code to create from OpenFirmware platform devices */
 201 #ifdef CONFIG_LEDS_GPIO_OF
 202 #include <linux/of_platform.h>
 203 #include <linux/of_gpio.h>
 204
 205 struct gpio_led_of_platform_data {
 206         int num_leds;
 207         struct gpio_led_data led_data[];
 208 };
 209
 210 static int __devinit of_gpio_leds_probe(struct of_device *ofdev,
 211                                         const struct of_device_id *match)
 212 {
 213         struct device_node *np = ofdev->node, *child;
 214         struct gpio_led_of_platform_data *pdata;
 215         int count = 0, ret;
 216
 217         /* count LEDs defined by this device, so we know how much to allocate */
 218         for_each_child_of_node(np, child)
 219                 count++;
 220         if (!count)
 221                 return 0; /* or ENODEV? */
 222
 223         pdata = kzalloc(sizeof(*pdata) + sizeof(struct gpio_led_data) * count,
 224                         GFP_KERNEL);
 225         if (!pdata)
 226                 return -ENOMEM;
 227
 228         for_each_child_of_node(np, child) {
 229                 struct gpio_led led = {};
 230                 enum of_gpio_flags flags;
 231                 const char *state;
 232
 233                 led.gpio = of_get_gpio_flags(child, 0, &flags);
 234                 led.active_low = flags & OF_GPIO_ACTIVE_LOW;
 235                 led.name = of_get_property(child, "label", NULL) ? : child->name;
 236                 led.default_trigger =
 237                         of_get_property(child, "linux,default-trigger", NULL);
 238                 state = of_get_property(child, "default-state", NULL);
 239                 if (state) {
 240                         if (!strcmp(state, "keep"))
 241                                 led.default_state = LEDS_GPIO_DEFSTATE_KEEP;
 242                         else if(!strcmp(state, "on"))
 243                                 led.default_state = LEDS_GPIO_DEFSTATE_ON;
 244                         else
 245                                 led.default_state = LEDS_GPIO_DEFSTATE_OFF;
 246                 }
 247
 248                 ret = create_gpio_led(&led, &pdata->led_data[pdata->num_leds++],
 249                                       &ofdev->dev, NULL);
 250                 if (ret < 0) {
 251                         of_node_put(child);
 252                         goto err;
 253                 }
 254         }
 255
 256         dev_set_drvdata(&ofdev->dev, pdata);
 257
 258         return 0;
 259
 260 err:
 261         for (count = pdata->num_leds - 2; count >= 0; count--)
 262                 delete_gpio_led(&pdata->led_data[count]);
 263
 264         kfree(pdata);
 265
 266         return ret;
 267 }
 268
 269 static int __devexit of_gpio_leds_remove(struct of_device *ofdev)
 270 {
 271         struct gpio_led_of_platform_data *pdata = dev_get_drvdata(&ofdev->dev);
 272         int i;
 273
 274         for (i = 0; i < pdata->num_leds; i++)
 275                 delete_gpio_led(&pdata->led_data[i]);
 276
 277         kfree(pdata);
 278
 279         dev_set_drvdata(&ofdev->dev, NULL);
 280
 281         return 0;
 282 }
 283
 284 static const struct of_device_id of_gpio_leds_match[] = {
 285         { .compatible = "gpio-leds", },
 286         {},
 287 };
 288
 289 static struct of_platform_driver of_gpio_leds_driver = {
 290         .driver = {
 291                 .name = "of_gpio_leds",
 292                 .owner = THIS_MODULE,
 293         },
 294         .match_table = of_gpio_leds_match,
 295         .probe = of_gpio_leds_probe,
 296         .remove = __devexit_p(of_gpio_leds_remove),
 297 };
 298 #endif
 299
 300 static int __init gpio_led_init(void)
 301 {
 302         int ret;
 303
 304 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 305         ret = platform_driver_register(&gpio_led_driver);
 306         if (ret)
 307                 return ret;
 308 #endif
 309 #ifdef CONFIG_LEDS_GPIO_OF
 310         ret = of_register_platform_driver(&of_gpio_leds_driver);
 311 #endif
 312 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 313         if (ret)
 314                 platform_driver_unregister(&gpio_led_driver);
 315 #endif
 316
 317         return ret;
 318 }
 319
 320 static void __exit gpio_led_exit(void)
 321 {
 322 #ifdef CONFIG_LEDS_GPIO_PLATFORM
 323         platform_driver_unregister(&gpio_led_driver);
 324 #endif
 325 #ifdef CONFIG_LEDS_GPIO_OF
 326         of_unregister_platform_driver(&of_gpio_leds_driver);
 327 #endif
 328 }
 329
 330 module_init(gpio_led_init);
 331 module_exit(gpio_led_exit);
 332
 333 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>");
 334 MODULE_DESCRIPTION("GPIO LED driver");
 335 MODULE_LICENSE("GPL");